1. Field of the Invention
The present invention relates to circuits, and in particular to bandgap reference circuits.
2. Description of the Related Art
Ideally, a bandgap reference circuit is intended to provide a substantially temperature-invariant reference voltage level to other circuits over a range of temperatures. The bandgap reference circuit is an electrical loop that needs a means of starting the circuit, such as a start-up circuit. Most of the time, the means of starting the bandgap reference circuit can consume current (i.e., drain power) and, in some cases, be a source of oscillation or instability.
A “positive offset” is defined as an output of an operational amplifier (op amp) being relatively low when the differential pair inputs of the op amp are connected to substantially the same voltage. Conversely, a “negative offset” causes the op amp output to be at a relatively high level. A “systematic offset” is an offset introduced by a design principle. A “spread offset” is an offset introduced by processing. An “artificial offset” is an offset introduced willingly by the designer.